Hybrid Vehicle Torque Control via Unified Reduction Factor
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Solution Overview
Problem
Conventional torque control methods for hybrid vehicles are overly complex due to variable constraints on engines and motor/generators, requiring excessive memory for optimal correction and separate battery management, which often leads to suboptimal control and potential overcharge or overdischarge issues.
Innovation Solution
A simplified torque control method that calculates a reduction factor based on the minimum reduction torque ratios of the engine and motor/generators, allowing for simultaneous control of torque and battery power, thereby stabilizing speed and charging/discharging operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If individual optimal correction is applied for each constraint change of engine and motor/generator, then control precision is improved, but device complexity increases excessively
Solution Approach 1:
The patent merges the separate optimal correction processes for engine and motor/generator constraints into a unified control method. By calculating a single reduction factor based on the minimum reduction torque ratio among all driving sources, the system achieves coordinated torque control without requiring separate complex correction algorithms for each component, thus maintaining control precision while reducing overall system complexity.
Solution Approach 2:
The reduction factor calculation method serves multiple functions simultaneously: it determines torque reduction for the engine, torque reduction for motor/generators, and battery power control all through a single universal calculation. This multi-functional approach eliminates the need for separate control algorithms for each component, resolving the contradiction between precision and complexity.
2Manufacturing precision
If multiple optimal map data are input for each condition, then control precision is improved, but memory capacity must be increased excessively
Solution Approach 1:
The patent extracts the essential control parameter (reduction torque ratio) from complex optimal map data and uses it to calculate a single reduction factor. This extraction approach maintains control precision by preserving the critical relationship between constraints and optimal torque while eliminating the need to store multiple comprehensive optimal maps, thereby significantly reducing memory requirements.
3Ease of operation
If separate battery management is conducted, then battery control is simplified, but overall control coordination deteriorates
Solution Approach 1:
The patent merges battery power control with the torque control of driving sources by using the same reduction factor for both. This integration ensures that battery power is automatically adjusted in coordination with engine and motor/generator torque, maintaining control coordination while keeping the management approach simple through the unified reduction factor mechanism.
Data Source
AI summary
A torque control system and method for a hybrid vehicle. More specifically, an optimal torque at a driving point of an engine, a maximum torque at a steady state of the engine, optimal torques at a driving point of two motor/generators and maximum torques at a steady state of the two motor/generators are input into a control unit. Then each reduction torque ratio of the engine and two the motor/generators is calculated by the control unit, and a reduction factor based on the reduction torque ratio of the engine and the two motor/generators is determined. Next, each target torque based on the reduction factor and the optimal torques of the engine and the two motor/generators is calculated, and each torque of the engine and motor/generators is controlled according to the each target torque.